Positive stop electrical switch

ABSTRACT

A positive stop electrical switch having two cup like housings the open end of each mates and closedly telescopes on the other causing the enclosed contacts to make and convey the electrical signal, thereon the contacts act as a positive stop, or if necessary the contacts in conjunction with the shoulder of the housings act as a positive stop.

Lowe

1 1 POSITIVE STOP ELECTRICAL SWITCH 3,383,487 5/1968 Wiener 200/168 G[76] Inventor: Charles Thomas Lowe, 5165 Torrey I Rd., Flint, Mich,48507 Primary ExaminerG. Rubinson Assistant Examiner-William J. Smith[22] Fled: 1973 3 Attorney, Agent, or FirmWodhams, Blanchard and 21Appl. No.: 345,089 Flynn [52] US. Cl. 200/302, 200/86 R, 200/159 R [57]ABSTRACT 20 0?1 9 1 5g g yi A positive stop electrical switch havingtwo-cup like f 200/155 C housings the openend of each mates and closedlytelescopes on the othercausing the enclosed contacts [56] ReferncesCited to make and convey the electrical signal, thereon the y contactsact as a positive stop, or if necessary the U T STATES PATENTS contactsin conjunction with the shoulder of the hous 857,446 6/1907 Comstock200/86 R ings act as a positive stop. 1,622,809 3/1927 Rodman 200/150 A1,935,838 11/1933 Efstathiou 200/86 R 7 Claims, 3 Drawing Figures I I;23 p 4 2 22 g 7 2/ v I 1 1 Jan. 21, 1975 POSITIVE STOP ELECTRICAL SWITCHThis invention relates to a'device having the duel functions ofconveying an electrical signal and being a positive stop.

The object of the invention is to provide an'electrical switch which .isan integral part of a positive stop such that the signal action and thestopping action occur simultaneously. I

This object is accomplished by providing a positive stop electricalswitch having two cup like housings in which the open end of each matesand closedly telescopes on the other. The base housing contains a ringlike contact having an external lead wire. Inside the ring contact is adisc like contact with an external lead wire. The ring contact, disccontact and base housing are insulated from each other. The operatorhousing encloses and is insulated from a disc contact. The machinecycleclosedly telescopes the housings causing the disc in the operator.housing to contact the ring and disc in the base housing. The contactsare so constructed and supported that upon closing they eitherindependently, orin conjunction with the shoulder of the housings,become a positive stop.

The advantages and economies of the positive stop electrical switch willbecome clear from the following detailed description, with reference tothe accompanying drawings, in which:

FIG. 1 is a plan view of the cup like base half of the invention showingthe inside arrangement.

FIG. 2 is a plan view of the cup like operator half of the inventionshowing the inside arrangement.

FIG. 3 is a cross sectional side view of the invention in its entiretytaken at line 1-1 FIG. 1 and line 22 FIG. 2.

The cup like base 1, preferrably made of metal,,has a circular cavitythe bottom portion of which is slightly enlarged so as to mechanicallyhold in place the insulating material 2 such as, for example, plastic(see FIG. 3). Embedded in the insulation 2 is a ring like contact 3 (seeFIG. 1 and FIG. 3) connected to an external lead wire 4 which exits thebase 1 through hole 5. Also embedded in the insulation 2 is a disc likecontact 6 connected to an external lead wire 7 which likewise exits thebase 1 through the holeS. The ring contact 3 and the disc contact 6 aretapered such that they are mechanically held in the insulation 2 (seeFIG. 3).

The base 1 is provided with an annular shoulder 8 having a series ofholes 9 for accepting the springs 10.

Annular grooves 11 are provided in the insulation 2 and an annulargroove 12 is provided at the outer edge of shoulder 8 (see FIG. 3).Thegrooves 11' andthe groove 12 accept sludgecaused by wear.

The annular notch 13 accepts the outer portion of the O-ring 14 andallows it to act asboth a seal and a retainer. The anti-friction insert15 in the base 1 aids the telescoping movement of the operator 20.

. The outer raised portion of the base 1 has annular sawteeth 16 forengaging and holding a protective and pliable band 17 such as, forexample, a rubber-band. Winged bosses 18 with holes 19 project from thebase I for mounting. The cup like operator 20', preferrably made ofmetal, is made simular to the base 1. The operator 20 has a circularcavity the bottom portion of which is slightly enlarged so as tomechanically hold the insulation 21. Embedded in the insulation 21 is adisc like contact 22 tapered such that it is mechanically held in place.The annular groove 23 holds the O-ring 14 in place. The outer raisedportion of the operator 20 has annular sawteeth 24 for holding the band17 in place.

' The springs 10 press against the shoulder 25 of the operator 20 tomaintain proper clearance between the operator contact '22 and the basecontacts 3 and 6 (see FIG. 3). To suppress arcing of said contacts whenthe electrical circuit is broken, the clearance gap between the contactsmay be partially filled with insulating oil.

In operation the positive stop limit switch is mounted to the stationarypart of a machine. The workhead of the machine, when near the end of itswork stroke, contacts the outer face of the operator 20. The force ofthe springs 10 is overcome and the operator 20 is forced toward thebase 1. As the operator contact 22 comes into contact with the basecontacts 3 and 6 the electrical signal is initiated (to return theworkhead) and simultaneously the device mechanically acts as a positivestop. The positive stop electrical switch has now performed its dualfunctions of conveying an electrical signal and thereon acting as apositive stop.

When the device is used on-small to medium size machines, the shoulder25 of operator 20 will be machined a few thousandths below the surfaceof contact 22. This allows the contacts 3, 6, and 22 to act as apositive stop without any support from the shoulder 25 of operator 20.When medium to large machinery is encountered the shoulder 25 ofoperator 20 will be machined even with the surface of contact 22 and theshoulder 8 of base 1 will be machined even with the surface of contact 3and contact 6. This allows said contacts and said shoulders to acttogether as a positive stop.

- Having thus described my invention I claim as new and desire to secureby Letters Patent:

1. A combined mechanical stop and electrical switch, comprising acuplike base housing and a cuplike operator housing disposed in opposedrelationship to one another and positioned in slidable telescopicrelationship to define a substantially closed chamber therebetween, eachof said housings defining therein an inside cavity, a body of insulatingmaterial substantially filling each of said cavities and being fixedrelative to the respec-' tive housing, an electrical contact embeddedwithin each body of insulated material with said electrical contacts asmounted on the opposed housings being deposed opposite one another andpositioned for contacting one another when said housings are slidablymoved toward one another, the cavity in one of said housings having abottom portion which is enlarged so as to mechanically hold the body ofinsulating material therein,

and the contact as associated with said one housing comprising a diskhaving a tapered edge which is embedded and mechanically held within therespective body of insulating material, the exposed surface of said diskbeing substantially flush with the open end of said one housing, saidone housing having an annular groove formed on the outer circumferencethereof, an annular seal ring disposed within said groove and sealinglyengaged between said pair of housings, and an annular flexible sealdisposed in surrounding relationship to and extending between said pairof housings.

2. A combined mechanical stop and electrical switch, comprising firstand second cuplike housings disposed opposite one another and positionedin sliding telescopic relationship to one another to define asubstantially closed chamber therebetween, said first housing definingtherein a first cavity which has a first body of insulating materialfixed therein and a first electrical contact embedded within said firstbody of insulating taining a spring, said second housing having a secondcavity formed in the bottom thereof and surrounded by said shoulder withsaid second cavity being filled with a second body of insulatingmaterial, the bottom portion of said second cavity being at leastslightly enlarged to mechanically hold said second body of insulatingmaterial therein, a tapered ringlike contact embedded and mechanicallyheld in said second body of insulating material, a tapered disk-shapedcontact 'disposed within said ringlike contact and embedded andmechanically held in said second body ofinsulating material, a pair ofexternal lead wires with one of said wires being connected to saidringlike contact and the other of said wires being conntected to saiddiskshaped contact, said wires extending through a hole provided in saidsecond housing, the exposed surfaces of said ringlike contact and saiddisk-shaped contact being substantially flush with the plane of saidannular shoulder, said second body of insulating material being providedwith an annular groove therein between said ringlike contact and saiddisk-shaped contact, said second body of insulating material having afurther annular groove formed therein between said ring-shaped contactand said shoulder, and said second housing having an annular grooveformed therein between said shoulder and said wall portion, said wallportion having an annular notch on the inside circumference thereofadapted to accommodate therein an annular sealing ring, an annularantifriction insert mounted on the inside circumference of said wallportion adjacent the open end of said second housing, and the outercircumference of said second housing having projection means positionedfor engagement with a flexible annular shield adapted to surroundand'extend between said first and second housings.

3. In an electrical switch device, the improvement comprising:

a first cup-shaped housing including a first base wall and a firstannular sidewall fixed to said base wall and projecting outwardlytherefrom, said first annular sidewall defining a first cavity therein;

a first body of insulating material positioned within said first cavityand fixed relative to said first housing;

a first electrical contact member fixedly mounted on said first body ofinsulating material, said first contact member having an exposed contactsurface which faces the open end of said first housing;

a second cup-shaped housing disposed opposite and slidablytelescopically mounted on said first cupshaped housing for defining asubstantially closed compartment therebetween, said second housingincluding a second base wall and a second annular sidewall fixed to saidsecond base wall and projecting outwardly therefrom, said first andsecond annular sidewalls being slidably telescopically received onewithin the other, and said second annular'sidewall defining a secondcavity which opens toward and is disposed opposite said first cavity;

a second block of insulating material disposed within said second cavityand fixed relative to said second housing;

a second electrical contact member fixedly mounted on said second blockof insulating material, said second contact member having an exposedcontact surface which faces toward the open end of said second housingmember whereby the exposed contact surfaces on said first and secondcontact member are disposed directly opposite one another;

said first and second housing being relatively slidably movable towardand away from one another between a first position wherein said exposedcontact surfaces are spaced from one another and a second positionwherein said exposed contact surfaces engage one another; and

mechanical stop means coacting between said first and second housingsfor limiting relative movement of said first housing toward said secondhousing, said stop means including a first stop surface associated withsaid first housing and a second stop surface fixedly associated withsaid second housing, said first and second stop surfaces being disposeddirectly opposite one another and spaced apart when said firstand saidsecond housings are in said first position, said stop surfaces beingdisposed in engagement with one another when said first and secondhousings are in said second position.

4. A device according to claim 3, wherein said first contact membercomprises a ringlike member, wherein said second contact membercomprisesa disklike member of a size sufficient to engage said ringlikemember, and wherein said first body of insulating material has a thirdcontact member fixedly mounted thereon and positioned within but spacedfrom said ringlike member, said third contact member having an exposedcontact surface thereon which is substantially flush with the contactsurface formed on said ringlike member, whereby said disklike memberengages both said ringlike member and said third contact member whensaid housings are in said second position, and a pair of electricalleads associated with said device and extending externally of said firsthousing, one of said leads being connected to said ringlike member andthe other of said leads being connected to said third contact member. 1

5. A device according to claim 3, wherein said first housing has anannular shoulder fixedly associated therewith and disposed within saidfirst annular sidewall, said annular shoulder being spaced axiallyinwardly from the free end of said first annular sidewall, and saidsecond annular sidewall being slidably telescopically received withinsaid first annular sidewall, and said second annular sidewall having thefree end thereof defining one of said stop surfaces thereon, and saidannular shoulder defining the other stop surface thereon.

6. A device acording to claim 5, further including an elongated flexibleannular sleeve disposed in surrounding relationship to and extendingaxially between said first and second housings.

7. A device according to claim 6, further including spring meanscoacting between said first and second housings for normally resilientlyurging same away from one another-to normally maintain said housings insaid first position.

1. A combined mechanical stop and electrical switch, comprising a cuplike base housing and a cuplike operator housing disposed in opposed relationship to one another and positioned in slidable telescopic relationship to define a substantially closed chamber therebetween, each of said housings defining therein an inside cavity, a body of insulating material substantially filling each of said cavities and being fixed relative to the respective housing, an electrical contact embedded within each body of insulated material with said electrical contacts as mounted on the opposed housings being deposed opposite one another and positioned for contacting one another when said housings are slidably moved toward one another, the cavity in one of said housings having a bottom portion which is enlarged so as to mechanically hold the body of insulating material therein, and the contact as associated with said one housing comprising a disk having a tapered edge which is embedded and mechanically held within the respective body of insulating material, the exposed surface of said disk being substantially flush with the open end of said one housing, said one housing having an annular groove formed on the outer circumference thereof, an annular seal ring disposed within said groove and sealingly engaged between said pair of housings, and an annular flexible seal disposed in surrounding relationship to and extending between said pair of housings.
 2. A combined mechanical stop and electrical switch, comprising first and second cuplike housings disposed opposite one another and positioned in sliding telescopic relationship to one another to define a substantially closed chamber therebetween, said first housing defining therein a first cavity which has a first body of insulating material fixed therein and a first electrical contact embedded within said first body of insulating material, the second housing having a wall portion wHich projects inwardly from the open end of the housing to a point about midway of the housing, said wall portion being of reduced thickness to define an inner annular shoulder at the inner end thereof, said shoulder having a plurality of openings formed therein each containing a spring, said second housing having a second cavity formed in the bottom thereof and surrounded by said shoulder with said second cavity being filled with a second body of insulating material, the bottom portion of said second cavity being at least slightly enlarged to mechanically hold said second body of insulating material therein, a tapered ringlike contact embedded and mechanically held in said second body of insulating material, a tapered disk-shaped contact disposed within said ringlike contact and embedded and mechanically held in said second body of insulating material, a pair of external lead wires with one of said wires being connected to said ringlike contact and the other of said wires being conntected to said disk-shaped contact, said wires extending through a hole provided in said second housing, the exposed surfaces of said ringlike contact and said disk-shaped contact being substantially flush with the plane of said annular shoulder, said second body of insulating material being provided with an annular groove therein between said ringlike contact and said disk-shaped contact, said second body of insulating material having a further annular groove formed therein between said ring-shaped contact and said shoulder, and said second housing having an annular groove formed therein between said shoulder and said wall portion, said wall portion having an annular notch on the inside circumference thereof adapted to accommodate therein an annular sealing ring, an annular antifriction insert mounted on the inside circumference of said wall portion adjacent the open end of said second housing, and the outer circumference of said second housing having projection means positioned for engagement with a flexible annular shield adapted to surround and extend between said first and second housings.
 3. In an electrical switch device, the improvement comprising: a first cup-shaped housing including a first base wall and a first annular sidewall fixed to said base wall and projecting outwardly therefrom, said first annular sidewall defining a first cavity therein; a first body of insulating material positioned within said first cavity and fixed relative to said first housing; a first electrical contact member fixedly mounted on said first body of insulating material, said first contact member having an exposed contact surface which faces the open end of said first housing; a second cup-shaped housing disposed opposite and slidably telescopically mounted on said first cup-shaped housing for defining a substantially closed compartment therebetween, said second housing including a second base wall and a second annular sidewall fixed to said second base wall and projecting outwardly therefrom, said first and second annular sidewalls being slidably telescopically received one within the other, and said second annular sidewall defining a second cavity which opens toward and is disposed opposite said first cavity; a second block of insulating material disposed within said second cavity and fixed relative to said second housing; a second electrical contact member fixedly mounted on said second block of insulating material, said second contact member having an exposed contact surface which faces toward the open end of said second housing member whereby the exposed contact surfaces on said first and second contact member are disposed directly opposite one another; said first and second housing being relatively slidably movable toward and away from one another between a first position wherein said exposed contact surfaces are spaced from one another and a second position wherein said exposed contact surfaces engage one another; and mechanical stop means coacting between said first and second housings for limiting relative movement of said first housing toward said second housing, said stop means including a first stop surface associated with said first housing and a second stop surface fixedly associated with said second housing, said first and second stop surfaces being disposed directly opposite one another and spaced apart when said first and said second housings are in said first position, said stop surfaces being disposed in engagement with one another when said first and second housings are in said second position.
 4. A device according to claim 3, wherein said first contact member comprises a ringlike member, wherein said second contact member comprises a disklike member of a size sufficient to engage said ringlike member, and wherein said first body of insulating material has a third contact member fixedly mounted thereon and positioned within but spaced from said ringlike member, said third contact member having an exposed contact surface thereon which is substantially flush with the contact surface formed on said ringlike member, whereby said disklike member engages both said ringlike member and said third contact member when said housings are in said second position, and a pair of electrical leads associated with said device and extending externally of said first housing, one of said leads being connected to said ringlike member and the other of said leads being connected to said third contact member.
 5. A device according to claim 3, wherein said first housing has an annular shoulder fixedly associated therewith and disposed within said first annular sidewall, said annular shoulder being spaced axially inwardly from the free end of said first annular sidewall, and said second annular sidewall being slidably telescopically received within said first annular sidewall, and said second annular sidewall having the free end thereof defining one of said stop surfaces thereon, and said annular shoulder defining the other stop surface thereon.
 6. A device acording to claim 5, further including an elongated flexible annular sleeve disposed in surrounding relationship to and extending axially between said first and second housings.
 7. A device according to claim 6, further including spring means coacting between said first and second housings for normally resiliently urging same away from one another to normally maintain said housings in said first position. 